Pulling system for parallel-wire strand

ABSTRACT

Apparatus for pulling parallel-wire strand, prior to winding on a takeup drum, including a clamping device comprising a plurality of clamping members arranged to define an opening for the wire strand and adapted to simultaneously apply pressure to all sides of the wire strand. The clamping device is mounted on a reciprocating carriage which advances short lengths of strand sequentially.

United States Patent Charles R. Nipp t Sr. Allentown. Pa.

Oct. 3, 1968 June 22, 197i Bethlehem Steel Corporation Inventor Appl. No Filed Patented Assignee PULLING SYSTEM FOR PARALLEL-WIRE STRAND 8 Claims, 9 Drawing Figs.

US. Cl 226/163 B65h 17/36 Field of Search .4 226/149, 150, 162-166 [5 6] References Cited UNITED STATES PATENTS 2,186,061 1/1940 Berg 226/165 X 2,788,120 4 /1957 Benjamin 226/165 Primary Examiner-Richard A Schacher AttorneyJoseph J. OKeefe ABSTRACT: Apparatus for pulling parallel-wire strand, prior to winding on a takeup drum, including a clamping device comprising a plurality of clamping members arranged to define an opening for the wire strand and adapted to simultaneously apply pressure to all sides of the wire strand. The clamping device is mounted on a reciprocating carriage which advances short lengths of strand sequentially.

PATENTEU JUN22|97| SHEU 1 OF 3 PATENTEUJUNZZISYI 3.586226 SHEET 3 OF 3 [F 42' .39\ 47 1. i* -J PULLING SYSTEM F OR PARALLEL-WIRE STRAND BACKGROUND OF THE INVENTION This invention relates generally to parallel-wire strand and more particularly to pulling the strand during fabrication thereof.

The development of parallel-wire strand for use in suspension bridge cables has provided a cable superior in strength and axial stiffness to the cables made of helical wire strands and is experiencing wide acceptance. The parallel-wire strands are formed by pulling a number of individual wires through forming dies which gather and bundle the wires into a compact strand. The compacted wires are bound together by wrapping a resilient tape around the strand at frequent spaced intervals. In order to pull the wires through the die evenly to form a balanced strand it is necessary to securely grip the strand with even pressure on all sides at a point beyond the forming dies so that there is no longitudinal or rotational slippage of the individual wires relative to each other.

Presently, parallel-wire strand is made by pulling out a fixed length, tag. 300 feet, with a winch-type apparatus, in short lengths of 20 to 30 feet for taping. This necessitates moving the hand tightened clamps and regripping the strand a number of times. Furthermore, the long length of strand requires extensive floor area and roller conveyor tables. Parallel strand cannot be pulled out with the winding drums. Means must be provided to adequately grip the strand so that all wires, internal and external, are advanced toward the winding drum or takeup reel.

It is therefore a primary object of the instant invention to provide apparatus for securely gripping the faces of a parallelwire strand and advancing the strand without distortion thereof.

It is a further object of the instant invention to provide an automatic, compact pulling apparatus adapted to advance short lengths of parallel-wire strand.

It is a still further object of the instant invention to provide a device with positive gripping action which will provide equal gripping forces on all faces of a multifaced strand and will maintain tension in the strand until it is adequately secured by wrapping.

SUMMARY OF THE INVENTION The instant invention accomplishes these objects by providing apparatus which is adapted to positively grip all faces of the parallel-wire strand in order to pull the strand through the forming dies from the supply reels.

The clamping device is mounted on a carriage designed to travel back and forth on a structure, alternately clamping and releasing the cable as short lengths of the cable are advanced sequentially toward the takeup reel. The apparatus comprises a plurality of clamping members mounted in a radial pattern on said carriage with means provided to maintain tension on the cable so as to prevent pullback or distortion when the reciprocating clamp is released. The sequence can be timed to permit taping of the strand and can be either automatic or manual operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a portion of a parallel-wire strand line employing apparatus according to the instant invention;

FIG. 2 is an elevational view of the apparatus of FIG. 1;

FIG. 3 is an enlarged sectional view of the clamping device;

FIG. 4 is a section through the clamping device taken on line 4-4 ofFIG. 3;

FIG. 5 is a detailed section of a portion of the apparatus taken on line 5-5 of FIG. 3;

FIG. 6 is an elevational view of the static clamp shown in the closed position;

FIG. 7 is a partial plan view of the operating links connccting the power unit to the clamping device taken on line 77 of FIG. 3, unnecessary details omitted for clarity;

FIG. 8 is an enlarged detail of the clamping arrangement of FIG. 4, and

FIG. 9 is an isometric view of a pair of jaws and pressure plates separated from their normal intercalated arrangement for purposes of clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to the drawings and to FIGS. 1 and 2 particularly in which a major portion of a line for fabricating parallel-wire strand such as is used on suspension bridges, etc. is seen. 'The strand 10 is seen leaving roller die 11, the last in a line of several roller dies which form the strand and prevent lagging of the wires. The strand then approaches the pulling stand 12 which advances short lengths of the strand sequentially onto roller table 13 and across traverse mechanism 14 which directs the completed strand onto takeup reel 15.

The pulling stand 12 comprises a supporting structure 16, a pair of static clamps 17, one mounted at each end of the pulling stand for reasons that will become evident, and a dynamic clamp 18. The dynamic clamp is mounted on a carriage 19 which is adapted for reciprocating movement on the supporting structure being driven by means of two chains 20, sprockets 21, reducer 22, and motor 23.

Referring to FIGS. 3 and 4 the dynamic clamp 18 will be seen to comprise a plurality of clamping members 24 mounted on the carriage 19 and adapted to receive and clamp the wire strand 10. The pictured embodiment comprises six clamping members 24 arranged in a radial ring about the wire strand pass line to define a hexagonal opening for parallel-wire strand having a hexagonal cross section. However, it will be clear that the instant invention can be adapted equally well to other sections of parallel-wire strand. Each of the clamping members 24 is provided with a cross brace 25 which spans between two spaced apart mounting plates 26 and 26'. One end of each of the aforesaid clamping members is pivotally attached to a cross brace 25. The cross braces are fixedly mounted, as by welding, to the mounting plates26 and 26 in a radial fashion about the central opening 27 in the mounting plates through which the parallel-wire strand 10 passes. Slots 28 are provided in the mounting plates 26 and 26 to receive the pressure plate ends 29 of clamping members 24 and to permit slidable movement therein. The details of the clamping members and the operation thereof will be explained in fuller detail later.

The aforementioned mounting plates 26 and 26 are mounted on channel members 30 which form a pan of the carriage frame 19. Wheels 31 are pivoted on the carriage frame channel members 30 adapted to travel back and forth in runway 32 at each side of the supporting structure 16. Runway 32 is formed simply by affixing top and bottom guide members, in this case angles, to the inside of top longitudinal members of the supporting structure 16. The carriage 19 further includes an operable crosshead 33 which is slidably mounted on carriage members 30.

A power unit 34 comprising a double acting pneumatic cylinder 35, valve unit 36 and fluid supply 37 is mounted on the mounting plates 26 and 26 completing the rigid carriage unit which comprises the power unit 34, mounting plates 26 and 26' and carriage supporting frame 19. The operating unit comprises the rod end 38 of the air cylinder 35, toggle links 42 and 42', toggle link assemblies 43, crosshead 33, connecting links 39 and 40 and pulling jaws 41 of the clamping device 18.

Still referring to FIGS. 3 and 4, the clamping mechanism will now be discussed in detail. The operating rod 38 of the power cylinder 35 is seen to be connected by means of a clevis 44 to operating links 45 and toggle link 42. The operating links 45 are keyed to shaft 46 and rotate responsive to movement of the power cylinder rod 38. Rotation of operating links 45 also causes movement of toggle link 42 which is pin connected to the top of crosshead 33. Shaft 46 is mounted in bearings 47 which are fixed to the outside of mounting plate 26'. Rotation of shaft 46 actuates the operating links 48 mounted on the ends of shaft 46 thereby also actuating connecting links 39 pinned at one end to operating links 48 and at the other end to toggle links 42. One end of toggle link 42' is anchored to carriage mounting plate 26' at 49. The other end connected at one end to the crosshead 33 and at the other end to toggle link assembly 43. Toggle link assembly 43 comprises links 40' connecting two pairs of links 43 to each other and to link 40 to form an operating unit. The pairs of links 43' are connected at one end to the cross brace member 25 and to slidable pressure plate 29 of the clamping member 24 at the other end. The radial disposition of the clamping members 24 with the wire strand pass line as a center forms a symmetrical articulated clamp which embraces the many sided cable 10 in a firm grip with equal pressure on all sides. Keeper plates 52 are provided to guide the pressure plates 29 in their travel back and forth from pressure on the strand 10 to release therefrom.

A series of pulling jaws or inserts 41 are mounted against the gripping faces of the clamping members 24 as seen in FIGS. 4 and 9 and are removably attached thereto by suitable securing means, e.g., machine screws. The design of the pulling jaws 41 provides each clamping member with aligning means intercalated with cooperating aligning means on each adjoining clamping member. One edge of each jaw member 41 has a projection 53 intercalated with a groove 54 on an opposite edge of an adjacent jaw member.

The toggle link assemblies 43 are provided with means as seen in FIG. to adjust the clamping members to properly orient them with respect to the strand. lnaccuracies in the machining of the many mechanical links in the toggle assembly as well as unevenness in wear necessitates occasional adjustment of each clamping member. The pin 55 connecting the toggle link assemblies to their respective anchorages on cross brace 25 is designed as a shaft having an eccentric central portion 56 and a spur gear 57, also eccentric, integral therewith. The shaft is further provided with a hex head 58 at one end for engagement by a wrench for turning. As the shaft is rotated the eccentric central portion 56 engaging the links 43 raises or lowers them as desired. A spur gear sector 59 is used to lock the adjustment in place by the simple means of a machine screw 60 through a hole in the sector aligned with a like hole in cross brace 25.

Means are provided adjacent the ends of the pulling stand supporting structure 16 as seen in FIGS. 1 and 2, to secure a section of the strand therebetween when the clamping members 24 are released from the strand. Static clamps 17, details of which are seen in FIG. 6, are mounted one at each end of the pulling stand 12. A double acting air cylinder 61 is mounted at the top of the static clamp mounting post 62. The rod end 63 of cylinder 61 is connected by means of a clevis 64 to a connecting link 65 which is further mechanically linked to clamping jaws 66. Actuation of the air cylinder 61 causes the jaws 66 to close on the strand 10 in a manner easily understood by those skilled in the art, and because the jaws are shaped to fit the cross section of the strand, grip the strand securely and evenly to prevent distortion of the individual wires in the strand. The two static clamps l7 acting simultaneously grip the section of strand between them to maintain the tension in the strand that has been developed by the pulling carriage 19. The pulling carriage clamp members 24 are then released from the strand and the carriage is returned to grip the strand again at the start of another cycle. Support rollers 70 are provided as seen in F IG. 7 to support the wire strand on the return cycle.

The following description of the operation of the pulling device of the instant invention, as seen in FIGS. 1 and 2, will clearly demonstrate the advantages and uniqueness of the apparatus.

The parallel-wire strand 10 formed by conventional methods passes through a series of roller dies 11 where it is bound at intervals by a resilient binding material 67 at stations located between the roller dies. The strand then enters the pulling stand 12 and is securely gripped by the clamping members of the dynamic clamp 18 which is mounted on the carriage 19 adapted to move back and forth within the limits of the pulling stand 12. The carriage drive unit 68 which comprises motor 23, reducer 22, shaft 69, sprockets 21 and chains 20, when activated causes the carriage 19 to move toward the takeup reel thus advancing a section of strand approximately the length of the pulling stand. When the carriage reaches the distal end of the stand, limit switches detect the presence of the carriage and cause an electrically controlled sequence to be set in motion including stopping drive motor 23, activating the static clamp 17 to securely grip the advance length of strand, withdrawal of the clamping members 24 from the strand and reversal of drive means 68 to return the dynamic pulling clamps to the proximal end of the pulling stand. On arrival of the carriage at the proximal end limit switches detect its presence and set in motion the sequence for once again clamping the pulling jaws 41 around the strand, releasing the static clamps 17 and actuating the drive means 68 to repeat the pulling cycle. Manual operation is available to the operator to override the automatic sequencing in the event that a mechanical sleeve splice or wire connector on one of the wires in the strand is in the clamping area. In this case the operator would simply move the carriage slightly to avoid the connector and the sequence of operations would resume.

A solenoid valve (not shown) is energized by the operator to initiate the clamping operation. Valve 36, FIG. 3, is opened allowing air from the supply source 37 to pass into the piston end of the double acting air cylinder 35 causing the rod end 38 of the piston to move outward therefrom. The interconnection between the air cylinder 38 and the crosshead 33 comprising mechanical linkage previously described will cause movement of the crosshead 33 in the direction of the takeup reel 15. The mechanical links connecting the crosshead 33 with the toggle link assemblies 43 on the clamping member 24 responsive to movement of crosshead 33 move the radially disposed clamping members 24 with pulling jaws 41 affixed thereto to advance toward the strand in embracing fashion. Positive gripping action provided by the toggle link arrangement assures equalization of forces on all sides of the strand.

As the pulling device advances the strand sequentially it is supported on a roller table 13, FIGS. 1 and 2, and is directed onto the takeup reel 15 by a traverse mechanism 14 which feeds the strand onto the reel in a traversing manner back and forth across the reel.

It is readily understood that the unique means for providing simultaneous action of the clamping members drawn forcibly toward the strand provides a clamp especially adapted to provide even clamping pressure from all sides of a hexagonal clamping device in order to exert a uniform clamping action upon all the internal as well as external wires of the hexagonal strand 10.

lclaim:

1. Apparatus for pulling parallel-wire strand comprising:

a. a supporting structure,

b. a carriage mounted on said supporting structure and adapted for reciprocating movement thereon,

c. means to actuate said carriage,

d. a plurality of clamping members mounted on said carriage adapted to receive and clamp said wire strand,

e. means for simultaneously actuating said clamping members to clamp said strand therebetween, and

f. aligning means along the edge of each clamping member overlapping with the cooperating aligning means on each adjoining clamping member.

2. Apparatus according to claim 1 further including:

g. means mounted adjacent the ends of said supporting structure to secure a section of said strand when said clamping members are released therefrom.

3. Apparatus according to claim 1 wherein the means recited in subparagraph (e) comprises:

a toggle link assembly connecting all of said clamping members to a single power means.

4. Apparatus according to claim 3 wherein said toggle link assembly includes a plurality of toggle links each pivotally connected at one end to one of said clamping members and at the other end to a crosshead which is actuated by said power means.

5. Apparatus according to claim 3 wherein said power 

1. Apparatus for pulling parallel-wire strand comprising: a. a supporting structure, b. a carriage mounted on said supporting structure and adapted for reciprocating movement thereon, c. means to actuate said carriage, d. a plurality of clamping members mounted on said carriage adapted to receive and clamp said wire strand, e. means for simultaneously actuating said clamping members to clamp said strand therebetween, and f. aligning means along the edge of each clamping member overlapping with the cooperating aligning means on each adjoining clamping member.
 2. Apparatus according to claim 1 further including: g. means mounted adjacent the ends of said supporting structure to secure a section of said strand when said clamping members are released therefrom.
 3. Apparatus according to claim 1 wherein the means recited in subparagraph (e) comprises: a toggle link assembly connecting all of said clamping members to a single power means.
 4. Apparatus according to claim 3 wherein said toggle link assembly includes a plurality of toggle links each pivotally connected at one end to one of said clamping members and at the other end to a crosshead which is actuated by said power means.
 5. Apparatus according to claim 3 wherein said power means includes a double acting air cylinder.
 6. Apparatus according to claim 3 wherein said toggle link assembly is provided with adjusting means to orient said clamping members with respect to said strand.
 7. Apparatus according to claim 1 wherein said parallel strand has a hexagonal cross section.
 8. Apparatus according to claim 7 wherein six clamping members are arranged in a radial ring to define a hexagonal opening. 